Datenblatt-Suchmaschine für elektronische Bauteile |
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ST3917BD Datenblatt(PDF) 1 Page - STMicroelectronics |
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ST3917BD Datenblatt(HTML) 1 Page - STMicroelectronics |
1 / 16 page ST3917A ST3917B SPEECH - TONE/PULSE DIALER - LED INDICATOR July 1996 SPEECH CIRCUIT . 2 TO 4 WIRES CONVERSION . PRESENT THE PROPER DC PATH FOR THE LINE CURRENT AND THE FLEXIBILITY TO ADJUST IT AND ALLOWPARALLEL PHONE OPERATION . SYMMETRICAL HIGH IMPEDANCE MICRO- PHONE INPUTS SUITABLE FOR DYNAMIC, ELECTRET OR PIEZOELECTRIC TRANSDUCER . ASYMMETRICAL EARPHONE OUTPUT SUIT- ABLE FOR DYNAMIC TRANSDUCER . LINE LOSS COMPENSATION FIXED INTER- NALLY BY A.G.C. . INTERNAL MUTING TO DISABLE SPEECH DURING DIALING AND EXTERNAL MUTING TO DISABLE TRANSMIT AMPLIFIER DURING CONVERSATION MODE . LED INDICATOR EITHER FOR KEYBOARD ILLU- MINATION (OR ON-LINE INDICATION) DURING DIALING AND CONVERSATION OR FOR TONE MODE INDICATION, THROUGH MU/MFI PIN DIALER CIRCUIT . STORE UP TO 32 DIGITS FOR LAST NUMBER REDIAL BUFFER, LNR IS INHIBITED IF THERE ARE MORE THAN 32 DIGITS STORED . ALLOWMIXED MODE DIALING IN PULSE MODE . PACIFIER TONE PROVIDES AUDIBLE INDI- CATION OF VALID KEY PRESSED IN A BUZZ- ER OR/AND IN THE EARPHONE . TIMED PABX PAUSE / 10PPS PULSE RATE . MAKE/BREAK RATIO : 40/60 (ST3917A) AND 33/67 (ST3917B) . 4 SELECTABLE OPTIONS ON FLASH DURA- TION AND SOFTSWITCH INHIBITION IN ONE OF THE OPTION WITH 100ms FLASH TIMING . 2 SELECTABLE OPTIONS : TRANSMIT MUTE TOGETHER WITH LED FOR KEYBOARD ILLUMI- NATION OR LED FOR TONE MODE INDICATION . CONTINUOUS TONE FOR EACH DIGIT UNTIL KEY RELEASE . USES INEXPENSIVE 3.579545MHz CERAMIC RESONATOR . POWERED FROM TELEPHONE LINE, LOW OPERATING VOLTAGE FOR LONG LOOP AP- PLICATION DESCRIPTION The device consists of the speech and the dialer func- tions. It provides the DC line interface circuit that termi- nates the telephone line, analog amplifier for speech transmission and necessary signals for either DTMF and pulse dialing. When mated with a tone ringer, a complete telephonecan be producedwith just two ICs. TheDC lineinterfacecircuit developsits ownlinevoltage acrossthedeviceandit is adjustableby external resistor to suit different country’s specification. A built-in LED driver can deliver excess line current to external LED indicator(s) during dialing and speech mode. The LED(s) can be used either for keyboard illumination purpose or for tone mode indication during softswitch and mixed mode dialing by connecting MU/MFI pin to VDDandGND or anyrow respectively.The LEDcurrent is limited to 17mA (typical). The speech network provides the two to four wires inter- face,electronic switchingbetweendialingandspeechand automaticgain control on transmit and receive. The dialing network buffers up to 32 digits into the LND memorythatcan be laterredialedwith asinglekeyinput. Users can store all 13 signalling keys and access several unique functions with single key entries. These functions include : Pause, Last Number Dialled (LND), Softswitch and Flash. (see Figure 1). The FLASH key simulates a hookflash to transfercalls or to activate other special features provided by the PABX or central office. The PAUSE key stores a timed pause in the number sequence. Redial is then delayed until an outside line can be accessed or some other activities occur before normal signalling resumes. A LND key automatically redials the last number dialed. Adedicatedpin MU/MFI is used to select the muting for transmit amplifier and lighted dial LED for keyboard illumination or a LED indicator for tonemode indication. The SEL pin allows selection of any one of the four possible Flash duration options. DIP28 (Plastic Package) ORDER CODES : ST3917AN - ST3917BN SO28 (Plastic Package) ORDER CODES : ST3917AD - ST3917BD 1/16 |
Ähnliche Teilenummer - ST3917BD |
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Ähnliche Beschreibung - ST3917BD |
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